U.S. patent application number 10/998367 was filed with the patent office on 2006-06-01 for bond pad for ball grid array package.
This patent application is currently assigned to Texas Instruments Incorporated. Invention is credited to Jerry Gomez Cayabyab, Mark Gerald Muyco Cruz, Ma Celine Ramirez Mandapat.
Application Number | 20060113684 10/998367 |
Document ID | / |
Family ID | 36566624 |
Filed Date | 2006-06-01 |
United States Patent
Application |
20060113684 |
Kind Code |
A1 |
Cruz; Mark Gerald Muyco ; et
al. |
June 1, 2006 |
Bond pad for ball grid array package
Abstract
A device (100) and a method (200) for controlling resin bleed,
the device comprising a substrate (105) having a surface (107), an
integrated circuit (115) having a plurality of leads (120)
extending therefrom, and an adhesive (125) comprising a plurality
of components. The adhesive (125) generally resides between the
surface (107) of the substrate (105) and the integrated circuit
(115), wherein the integrated circuit is generally bonded to the
substrate. The device (100) further comprises a plurality of
electrically-conductive bonding pads (122) associated with the
surface (107) of the substrate and a plurality of studs (135)
respectively formed over the plurality of bonding pads. A plurality
of leads (120) are electrically connected to a top surface (137) of
the each respective stud (135), wherein a height (140) of each stud
is defined between the respective bonding pad (122) and the top
surface of the stud, and wherein the height of the each stud
generally prevents one or more of the plurality of components from
bleeding onto the top surface thereof.
Inventors: |
Cruz; Mark Gerald Muyco;
(Baguio City, PH) ; Cayabyab; Jerry Gomez; (Baguio
City, PH) ; Mandapat; Ma Celine Ramirez; (Baguio
City, PH) |
Correspondence
Address: |
TEXAS INSTRUMENTS INCORPORATED
P O BOX 655474, M/S 3999
DALLAS
TX
75265
US
|
Assignee: |
Texas Instruments
Incorporated
|
Family ID: |
36566624 |
Appl. No.: |
10/998367 |
Filed: |
November 29, 2004 |
Current U.S.
Class: |
257/784 ;
257/667; 257/676; 257/783; 257/E21.505; 257/E23.068 |
Current CPC
Class: |
H01L 2924/00014
20130101; H01L 2924/0665 20130101; H01L 24/32 20130101; H01L
2224/27013 20130101; H01L 2224/48465 20130101; H01L 2924/01079
20130101; H01L 2224/2919 20130101; H01L 2224/49171 20130101; H01L
2224/73265 20130101; H01L 2924/00014 20130101; H01L 2224/05639
20130101; H01L 2224/05644 20130101; H01L 2224/48095 20130101; H01L
2224/48095 20130101; H01L 2924/0665 20130101; H01L 2924/15787
20130101; H01L 24/83 20130101; H01L 2924/01047 20130101; H01L 24/48
20130101; H01L 2224/05624 20130101; H01L 2924/01028 20130101; H01L
2224/05599 20130101; H01L 2224/48227 20130101; H01L 2924/00
20130101; H01L 2224/48095 20130101; H01L 2924/0665 20130101; H01L
2924/00 20130101; H01L 2924/00 20130101; H01L 2924/00 20130101;
H01L 2224/32225 20130101; H01L 2224/45099 20130101; H01L 2924/00014
20130101; H01L 2924/00 20130101; H01L 2924/00 20130101; H01L
2924/00012 20130101; H01L 2224/48227 20130101; H01L 2224/48465
20130101; H01L 2224/32225 20130101; H01L 2924/00 20130101; H01L
2224/48227 20130101; H01L 2924/00 20130101; H01L 2924/00 20130101;
H01L 2924/00 20130101; H01L 2224/48227 20130101; H01L 2224/48227
20130101; H01L 2224/49171 20130101; H01L 2224/48465 20130101; H01L
23/49811 20130101; H01L 2224/73265 20130101; H01L 2924/01006
20130101; H01L 2224/05666 20130101; H01L 2224/48465 20130101; H01L
2924/01082 20130101; H01L 2924/14 20130101; H01L 2224/05155
20130101; H01L 2924/01029 20130101; H01L 2924/07802 20130101; H01L
2224/05599 20130101; H01L 2924/15787 20130101; H01L 24/73 20130101;
H01L 2224/49171 20130101; H01L 2224/2919 20130101; H01L 2224/32225
20130101; H01L 2224/48227 20130101; H01L 2224/73265 20130101; H01L
2924/01013 20130101; H01L 2924/01022 20130101; H01L 2224/05647
20130101; H01L 2224/05655 20130101; H01L 2224/48465 20130101; H01L
2224/8385 20130101; H01L 2924/00014 20130101; H01L 24/49 20130101;
H01L 2924/01033 20130101; H01L 2924/014 20130101 |
Class at
Publication: |
257/784 ;
257/783; 257/676; 257/667 |
International
Class: |
H01L 23/52 20060101
H01L023/52; H01L 23/48 20060101 H01L023/48; H01L 23/495 20060101
H01L023/495 |
Claims
1. A device for controlling a bleed of resin, the device
comprising: a substrate having a surface; an integrated circuit
having a plurality of leads extending therefrom; an adhesive
comprising a plurality of components, wherein the adhesive
generally resides between the surface of the substrate and the
integrated circuit, therein generally bonding the integrated
circuit to the substrate; a plurality of electrically-conductive
bonding pads associated with the surface of the substrate; and a
plurality of studs respectively formed over the plurality of
bonding pads, wherein the plurality of leads are electrically
connected to a top surface of the each respective stud, wherein a
height of each stud is defined between a top surface of the
respective bonding pad and the top surface of the respective stud,
and wherein the height of the each stud generally prevents one or
more of the plurality of components from bleeding onto the top
surface thereof.
2. The device of claim 1, wherein the plurality of studs are
comprised of one or more of a metal and a metal alloy.
3. The device of claim 2, wherein the plurality of studs are
comprised of one or more copper, aluminum, gold, silver, nickel,
and titanium.
4. The device of claim 2, wherein the plurality of studs are
respectively electroplated over the plurality of bonding pads.
5. The device of claim 2, wherein the plurality of studs are
respectively silk-screened over the plurality of bonding pads.
6. The device of claim 1, wherein the one or more of the plurality
of bonding pads are electrically connected to one or more other
electrical devices associated with the substrate.
7. The device of claim 1, wherein the height of each stud is
between approximately ten microns and approximately eighteen
microns.
8. The device of claim 1, wherein adhesive comprises a fluid-like
resin.
9. The device of claim 8, wherein the height of each stud is
associated with a viscosity of the resin.
10. The device of claim 1, wherein the substrate further comprises
a ball-grid array.
11. A method for controlling resin bleed, the method comprising:
providing a substrate having a surface, wherein an interior region
and peripheral region are generally defined, and wherein the
substrate further comprises a plurality of bonding pads associated
with the peripheral region of the surface; forming a plurality of
studs of the respective plurality of bonding pads; applying an
adhesive having a plurality of components to one or more of the
interior region of the substrate and an integrated circuit having a
plurality of leads extending therefrom; placing the integrated
circuit over the interior region of the substrate, wherein the
adhesive generally bonds the integrated circuit to the substrate;
and electrically connecting the plurality of leads to a top surface
of the respective plurality of studs, wherein a height of the studs
generally prevents a bleed of one or more of the plurality of
components onto the top surface of the plurality of studs.
12. The method of claim 11, wherein forming the plurality of studs
comprises electroplating a metal or metal alloy onto the plurality
of bonding pads.
13. The method of claim 12, wherein the metal comprises one or more
copper, aluminum, gold, silver, nickel, and titanium.
14. The method of claim 11, wherein forming the plurality of studs
comprises silk-screening a metal or metal alloy over the plurality
of bonding pads.
15. The method of claim 11, further comprising curing the adhesive
prior to forming the plurality of studs.
16. The method of claim 15, wherein curing the adhesive comprises
an application of heat thereto.
17. The method of claim 11, wherein the adhesive comprises a
fluid-like resin having a viscosity associated therewith, wherein
the height of the plurality of studs is associated with the
viscosity of the resin.
18. The method of claim 11, wherein the substrate comprises a
ball-grid array.
19. The method of claim 18, further comprising coupling the
ball-grid array to another device.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to semiconductor
devices, and more particularly to a device for controlling a
bleeding of resin on a substrate.
BACKGROUND OF THE INVENTION
[0002] In the semiconductor processing industry, various individual
components are combined in order to form an integrated device. For
example, in flip-chip or wire-bond semiconductor processing, two or
more components may be bonded to one another for purposes of
electrical interconnection, heat dissipation, ease of
manufacturing, or the like. For example, a conventional electronic
device 10 is illustrated in FIG. 1A, wherein the device (e.g., a
"ball grid array" package) may be electrically coupled to one or
more other electronic components (not shown). The device 10, for
example, comprises a plurality of solder balls (not shown)
associated with the substrate, wherein the solder balls generally
provide an electrical connection between the device and the other
electronic component(s).
[0003] In a typical device 10, a die 12 is coupled to a substrate
14, wherein the die and substrate are physically bonded to one
another, as well as electrically connected to one another. The die
12, for example, comprises an integrated circuit 15, wherein a
plurality of electrically conductive leads 16 extend therefrom, and
wherein the plurality of leads are operable to electrically connect
the die to the substrate 14. In conventional processing, prior to
electrically connecting the die 12 to the substrate 14, the die and
substrate are physically bonded to one another via an adhesive 18
that has been applied to one or more of the die and the substrate.
Conventionally, the adhesive 18 comprises a fluid-like epoxy that
is operable to be cured by an application of heat thereto (e.g., a
"baking" process), thus generally bonding the die 12 to the
substrate 14.
[0004] Once the die 12 and substrate 14 are physically bonded to
one another, the plurality of leads 16 associated with the die may
be electrically connected to a plurality of bonding pads 20
associated with the substrate, thus electrically coupling the die
to the substrate. For example, after the adhesive 18 is cured, each
of the plurality of leads 16 is soldered to a respective bonding
pad 20, wherein the plurality of leads are further operable to
electrically connect the die 12 to the one or more other electronic
components (not shown) associated with the device 10. In
conventional processing, however, the connection of the leads 16 to
the bonding pads 20 can be deleteriously affected if one or more
constituents of the adhesive 18 bleeds onto one or more of the
bonding pads 18. For example, in conventional processing, the
adhesive 18 comprises a fluid-like resin 22 that will tend to bleed
onto a surrounding region 24 of the surface 26 of the substrate 14
prior to the curing of the adhesive (e.g., during the time that
elapses between the application of the adhesive and the baking
process).
[0005] As illustrated in FIG. 1A, and further in the partial
cross-section of FIG. 1B, such a bleeding of the resin 22 has a
potential to contaminate one or more of the bonding pads 20, thus
deleteriously affecting the bonding of the leads 16 thereto. For
example, conventional bonding pads 20 are generally associated with
the surface 26 of the substrate 14, wherein the bonding pads have
been generally exposed in previous processing performed on the
substrate, such as via an etching process performed on the surface
of the substrate. Accordingly, a top surface 28 of each of the
bonding pads 20 is generally associated with the surface 26 of the
substrate 14. Consequently, the resin 22, upon bleeding into the
surrounding region 24 of the surface 26 of the substrate 14, can
easily bleed onto the top surface 28 of one or more of the bonding
pads 20, such as by capillary action. Once the resin 22 has bled
onto the top surface 28 of one or more of the bonding pads 20,
capillary forces associated with the top surface of the bonding
pads will have a tendency to pull even greater amounts of resin
onto the bonding pads. Therefore, upon reaching the surrounding
region 24, the resin 22 has a great potential to contaminate the
top surface 28 of the bonding pads 20, wherein the contamination
can deleteriously affect the electrical connection of the leads 16
thereto. For example, "non-stick" issues can arise, wherein the
resin 22 residing on the top surface 28 of the bonding pad 20
generally causes a poor solder connection 30 between the lead 16
and the bonding pad, thus leading to a potential failure of the
device 10.
[0006] Conventionally, undesirable affects from the bleed of resin
22 are minimized by providing a large bleed area 32 on the
substrate 14 for the resin to bleed onto, thus locating the bonding
pads 20 at a relatively large distance from the die 12. However, as
real estate on substrates becomes more and more valuable due to
ever decreasing sizes of associated electronic devices, providing
such a large bleed area 32 becomes less practical. Accordingly, a
need exists in the art for an economical device for preventing
resin bleed onto bonding pads, such that a size of the device can
be minimized, and wherein reliable electrical connections can be
made between the respective leads and bonding pads.
SUMMARY OF THE INVENTION
[0007] The following presents a simplified summary of the invention
in order to provide a basic understanding of some aspects of the
invention. This summary is not an extensive overview of the
invention. It is intended to neither identify key or critical
elements of the invention nor delineate the scope of the invention.
Its purpose is to present some concepts of the invention in a
simplified form as a prelude to the more detailed description that
is presented later.
[0008] The present invention is generally directed toward a bleed
control device and method for controlling a bleed of resin on a
substrate, wherein the bleed control device generally provides a
more reliable electrical connection between various components than
other conventional devices. In accordance with one exemplary aspect
of the invention, the device comprises a substrate, such as a
substrate for a ball-grid array package, wherein the substrate has
a surface having an interior region and a peripheral region
generally defined thereon. One or more electrical devices, such as
an integrated circuit or flip chip are further associated with the
interior region of the substrate.
[0009] In accordance with one aspect of the invention, the
integrated circuit is bonded to the substrate via an adhesive,
wherein the adhesive is comprised of a plurality of components,
such as a fluid-like resin. The adhesive generally resides on the
surface of the substrate in the interior region, wherein the
integrated circuit generally resides over the adhesive, and wherein
a bond between the substrate and the integrated circuit is
generally defined. The integrated circuit, for example, comprises a
plurality of leads extending therefrom, wherein the plurality of
leads are operable to electrically connect the integrated circuit
to one or more devices associated with the substrate.
[0010] In accordance with one exemplary aspect of the invention,
the bleed control device comprises a plurality of
electrically-conductive bonding pads associated with the surface of
the substrate. For example, the plurality of bonding pads are
generally associated with the surface of the substrate, wherein the
substrate has been etched in order to reveal a top surface of the
plurality of bonding pads. According to the present invention, a
plurality of studs are formed over the respective plurality of
bonding pads, wherein the plurality of leads are electrically
connected to a top surface of the each respective stud. For
example, the plurality of studs are comprised of a metal or a metal
alloy, wherein the plurality of studs are electroplated or
silk-screened onto the top surface of plurality of bonding pads,
therein providing an electrical connection thereto.
[0011] According to another exemplary aspect of the present
invention, a height of each stud is defined between the top surface
of each respective bonding pad and the top surface of each stud.
Each stud furthermore generally prevents one or more of the
plurality of components of the adhesive from bleeding onto the top
surface of the stud, due, at least in part, to the height of each
stud. For example, the height of each stud is associated with a
viscosity or bleed capacity of the resin. For instance, the height
of each stud is between approximately ten microns and eighteen
microns. The plurality of studs, for example, are formed over the
plurality of bonding pads prior to the application of adhesive onto
one or more of the integrated circuit and substrate, wherein the
electrical connections of the studs to the bonding pads are
substantially robust. The plurality of studs further generally
prevent the bleed of resin from deleteriously contacting the top
surface of the studs, therein advantageously affecting the
electrical connection of the plurality of leads to the studs, and
thus, the electrical connection of the integrated circuit to the
substrate.
[0012] To the accomplishment of the foregoing and related ends, the
invention comprises the features hereinafter fully described and
particularly pointed out in the claims. The following description
and the annexed drawings set forth in detail certain illustrative
embodiments of the invention. These embodiments are indicative,
however, of a few of the various ways in which the principles of
the invention may be employed. Other objects, advantages and novel
features of the invention will become apparent from the following
detailed description of the invention when considered in
conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1A is a plan view of a typical substrate illustrating a
bleed of resin onto the substrate.
[0014] FIG. 1B is a partial cross-sectional view of the
conventional substrate of FIG. 1A.
[0015] FIG. 2A is a plan view of an exemplary device for preventing
resin bleed in accordance with one exemplary aspect of the present
invention.
[0016] FIG. 2B is a partial cross-sectional view of the device of
FIG. 2A in accordance with another exemplary aspect of the
invention.
[0017] FIG. 3 is a block diagram of an exemplary method for
controlling a resin-bleed on a substrate in accordance with another
aspect of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The present invention is directed towards a device for
controlling a bleed of resin on a substrate. More particularly, the
present invention provides a cost-effective solution for generally
preventing resin bleed onto a bonding pad associated with the
substrate. Accordingly, the present invention will now be described
with reference to the drawings, wherein like reference numerals are
used to refer to like elements throughout. It should be understood
that the description of these aspects are merely illustrative and
that they should not be taken in a limiting sense. In the following
description, for purposes of explanation, numerous specific details
are set forth in order to provide a thorough understanding of the
present invention. It will be evident to one skilled in the art,
however, that the present invention may be practiced without these
specific details.
[0019] Referring now to the figures, FIG. 2A illustrates an
exemplary assembled electronic device 100 in accordance with one
aspect of the present invention. The device 100, for example,
comprises a substrate 105, such as a printed circuit board (PCB) or
a ceramic or semiconductive substrate, wherein a surface 107 of the
substrate is generally defined. An interior region 108 and a
peripheral region 110 of the surface 107 are further defined,
wherein an integrated circuit 115 generally resides within the
interior region of the assembled device 100. The integrated circuit
115, for example, comprises a plurality of leads 120, wherein the
plurality of leads are electrically connected to the integrated
circuit and extend therefrom. During an assembly of the device 100,
the plurality of leads 120 are operable to be electrically
connected to a plurality of bonding pads 122 (e.g., also referred
to as "stitch pads") associated with the substrate 105, as will be
discussed infra. The plurality of bonding pads 122, for example,
are generally defined during a mask and etch process performed on
the substrate 105, wherein the plurality of bonding pads are
associated with a wiring layer (not shown) residing beneath the
surface 107 of the substrate. Thus, the plurality of bonding pads
122 are generally exposed after the etch of the surface 107 of the
substrate 105, wherein the plurality of leads 120 can be
subsequently electrically connected thereto.
[0020] In accordance with one exemplary aspect of the invention,
once the plurality of bonding pads 122 are defined, the integrated
circuit 115 is generally affixed to the surface 107 of the
substrate 105 in the interior region 108 thereof via an adhesive
125. For example, during the assembly of the device 100, the
adhesive 125 is applied to one or more of the interior region 108
of the surface 107 of the substrate 105 and a backside (not shown)
of the integrated circuit 115, wherein the integrated circuit is
subsequently placed over the interior region, therein substantially
adhering the integrated circuit to the substrate via the adhesive.
The adhesive 125 may be further curable by an application of heat
thereto (e.g., at a temperature of approximately 150.degree. C.),
wherein the integrated circuit 115 is generally bonded to the
substrate 105 upon curing of the adhesive.
[0021] In one example, the adhesive 125 comprises of a thermo-set
epoxy, wherein the epoxy is further comprised of a plurality of
components. For example, the adhesive 125 comprises a resin 130
that resin has a tendency to leech or bleed onto the surface 107 of
the substrate 105 prior to, or during, the curing of the adhesive.
Typically, after the adhesive 125 is applied, but prior to the
adhesive curing, the resin 130 is operable to leach out of
suspension from the adhesive and to bleed onto the peripheral
region 110 of the surface 107 of the substrate 105. In conventional
processing, such a bleed of resin 130 can have deleterious effects
on the electrical connection of the plurality of leads 120 to the
substrate 105, since the leads are conventionally soldered or
stitched directly onto the bonding pads 122 after the adhesive 125
is cured. Thus, conventionally, if the resin 130 were to bleed onto
one or more of the plurality of bonding pads 122 prior to the
adhesive 125 curing, a respective one or more of the plurality of
leads 120 may have a tendency to release from the respective
bonding pad as a result of poor adhesion due to the resin, thus
leading to a potential electrical failure.
[0022] Therefore, in accordance with the present invention, a
plurality of studs 135 are provided, wherein each stud is
associated with a respective one of the plurality of bonding pads
122. The plurality of studs 135, for example, are formed over the
plurality of bonding pads 122 prior to the application of the
adhesive 125 onto the substrate 105, as will be discussed infra.
FIG. 2B illustrates a partial cross-section of the device 100 of
FIG. 2A, wherein the plurality of leads 120 electrically connect
the integrated circuit 115 to the substrate 105 via the respective
plurality of studs 135 and bonding pads 122. The bonding pads 122,
for example, may be further electrically connected other wiring or
components (not shown) associated with the substrate 105, wherein
the device 100 is operable to be electrically coupled other
electronic devices (not shown).
[0023] In accordance with the present invention, each of the
plurality of studs 135, for example, is formed over the respective
bonding pad 122 prior to the application of the adhesive 125 onto
the surface 107 of the substrate 105. Each of the plurality of
studs 135 further has a top surface 137 associated therewith,
wherein a height 140 of each of the plurality of studs 135, for
example, is generally defined by a distance between the top surface
137 of the stud and a top surface 142 of each bonding bad. The
height 140 of the plurality of studs 135, for example, is
determined based on several factors, such as one or more of a
composition of the resin 130 (e.g., a viscosity associated with the
resin), a composition of the plurality of studs (e.g., a surface
finish of the studs), and a distance 144 between the plurality of
bonding pads 122 and a fillet 145 of adhesive that is extruded
after the joining of the integrated circuit 115 to the substrate
105. For example, the height 140 of the plurality of studs 135
(e.g., a height of approximately between 10 microns and 18 microns)
is selected such that the resin 130 is generally prevented from
bleeding onto the top surface 137 of the plurality of studs by
gravitational force, wherein the top surface of each stud is
substantially higher than the top surface 142 of the respective
bonding pad 122. In accordance with another example, the height 140
of the plurality of studs 135 is provided such that a capillary
action of the resin 130 is overcome by gravitational forces, thus
generally preventing the resin from being pulled onto the top
surface 137 of the plurality of studs. Accordingly, the plurality
of studs 135 are operable to generally control the flow of resin
130, such that the resin is generally prevented from flowing onto
the top surface 137 of each of the plurality of studs.
[0024] According to another exemplary aspect of the invention, the
plurality of studs 135 are electrically conductive, and are
operable to be formed or placed over the top surface 142 of each
the respective plurality of bonding pads 122, thus providing an
electrical connection to the plurality of bonding pads. For
example, the plurality of studs 135 are comprised of a material
that is electrically and physically compatible with the plurality
of bonding pads 122, thus providing a good electrical connection
between each respective stud and bonding pad. According to one
example, the plurality of studs 135 are comprised of a similar
material as the plurality of bonding pads 122. For instance, the
plurality of studs 135 are comprised of a metal or metal alloy
comprising one or more of copper, silver, gold, nickel, aluminum,
and titanium, wherein the one or more metals are plated (e.g.,
electroplated) over the bonding pads 122. Alternatively, the
plurality of studs 135 are soldered or otherwise coupled to the
plurality of bonding pads 122 after the bonding pads are
formed.
[0025] In another alternative, the plurality of studs 135 are
formed over the plurality of bonding pads 122 by a silk-screening
process. In yet another example, the bonding pads 122 are formed on
the substrate 105 in conjunction with a formation of one or more
other metal features (not shown) associated with the substrate,
such as during a formation various wiring lines associated with the
electrical connection of the integrated circuit 115 to the one or
more other components (not shown). However, it should be noted that
in order to achieve the acceptable height 140 of the plurality of
studs 135, a separate formation process may be performed to form
the plurality of studs, and any such formation is contemplated as
falling within the scope of the present invention.
[0026] In a preferred embodiment, the plurality of studs 135 are
comprised of copper or an alloy of copper, wherein the copper is
electroplated to a height 140 of approximately 10-18 microns. As
stated previously, the plurality of studs 135 advantageously
provide a substantial differential in distance between the surface
107 of the substrate 105 and the top surface 137 of each stud,
wherein such a differential generally prevents the bleed, or flow,
of resin 130 onto the top surface of the plurality of studs. Again,
preventing the resin 130 from bleeding onto the top surface 137 of
each of the plurality of studs 135 generally permits a good
electrical connection between the plurality of leads 120 and the
plurality of studs. Accordingly, the plurality leads 120 can be
soldered or otherwise electrically connected to the plurality of
studs 135 in a highly reliable manner, wherein the electrical
connections between the leads and studs is substantially robust.
Furthermore, the plurality of studs 135 generally permit a tight
ratio between a size of the integrated circuit 115 and a size of
the substrate 105 (e.g., generally related to the substantially
small distance 144 between the plurality of bonding pads 122 and
the fillet 145 of adhesive 125), without sacrificing production
yield due to non-stick of leads 120 caused by resin bleed 130.
[0027] According to still another exemplary aspect of the present
invention, FIG. 3 is a schematic block diagram illustrating an
exemplary method 200 for controlling a bleed of resin on a
substrate. While exemplary methods are illustrated and described
herein as a series of acts or events, it will be appreciated that
the present invention is not limited by the illustrated ordering of
such acts or events, as some steps may occur in different orders
and/or concurrently with other steps apart from that shown and
described herein, in accordance with the invention. In addition,
not all illustrated steps may be required to implement a
methodology in accordance with the present invention. Moreover, it
will be appreciated that the methods may be implemented in
association with the systems illustrated and described herein as
well as in association with other systems not illustrated.
[0028] As illustrated in FIG. 3, the method 200 begins with act
205, wherein a substrate, such as a printed circuit board or
ceramic substrate, is provided, wherein the substrate has a surface
associated therewith. In accordance with one exemplary aspect of
the invention, an interior region and peripheral region of the
surface are generally defined, wherein the substrate further
comprises a plurality of bonding pads associated with the
peripheral region of the surface. In act 210, a plurality of studs
are formed over the respective plurality of bonding pads. For
example, the plurality of studs are formed by electroplating or
silk-screening a metal onto a top surface of the plurality of
bonding pads, wherein a reliable electrical connection between the
respective plurality of studs and bonding pads is formed.
[0029] In act 215, an adhesive is applied to one or more of the
interior region of the substrate and an integrated circuit, wherein
the integrated circuit comprises a plurality of leads extending
therefrom. The adhesive, for example, comprises one or more
components, such as a fluid-like resin. In act 220, the integrated
circuit is placed over the interior region of the substrate,
wherein the adhesive generally bonds the integrated circuit to the
substrate. According to one example, the adhesive is then
substantially cured, such as by an application of heat thereto. In
act 225, the plurality of leads are electrically connected to a top
surface of the respective plurality of studs, wherein a height of
the studs generally prevents a bleed of one or more of the
plurality of components onto the top surface of the plurality of
studs.
[0030] Although the invention has been shown and described with
respect to a certain aspect or various aspects, it is obvious that
equivalent alterations and modifications will occur to others
skilled in the art upon the reading and understanding of this
specification and the annexed drawings. In particular regard to the
various functions performed by the above described components
(assemblies, devices, circuits, etc.), the terms (including a
reference to a "means") used to describe such components are
intended to correspond, unless otherwise indicated, to any
component which performs the specified function of the described
component (i.e., that is functionally equivalent), even though not
structurally equivalent to the disclosed structure which performs
the function in the herein illustrated exemplary embodiments of the
invention. In addition, while a particular feature of the invention
may have been disclosed with respect to only one of several aspects
of the invention, such feature may be combined with one or more
other features of the other aspects as may be desired and
advantageous for any given or particular application. Furthermore,
to the extent that the term "includes" is used in either the
detailed description or the claims, such term is intended to be
inclusive in a manner similar to the term "comprising."
* * * * *